Ink jet printing refers to a method of forming type characters on paper by ejecting ink droplets from a print head through one or more nozzles. Several schemes are utilized to control the deposition of the ink droplets to form the desired characters. For example, one method comprises deflecting electrically charged droplets by electrostatic means. Another method comprises the ejection of single droplets under the control of a piezoelectric device.
Since the jets through which the very fine droplets are ejected are prone to clogging, it is advantageous in the art to employ inks of the so-called non-drying type which function by quickly penetrating the paper fibers, thus giving the appearance of being dry to the touch while still possessing a quantity of relatively low vapor pressure solvent. In fact, the time for the solvent to actually evaporate is often in excess of 12 hours.
The requirements for such inks have heretofore precluded the development of a satisfactory transparency printing substrate.
U.S. Pat. No. 4,371,582, issued Feb. 1, 1983, is directed to an ink jet recording sheet containing a basic latex polymer. When ink jet recording is applied on the ink jet recording sheet containing a basic polymer latex with an aqueous ink containing a direct dye or an acid dye having an anionic dissociable group, the dye in the aqueous ink is ionically bonded with the basic polymer latex in the recording sheet.
The basic polymer latex is represented by the formula: EQU (A).sub.x (B).sub.y (C).sub.z
wherein (A) represents a polymeric unit formed by copolymerizing a copolymerizable monomer containing a tert-amino group or a quaternary ammonium group; (B) represents a polymeric unit formed by copolymerizing a copolymerizable monomer containing at least two ethylenically unsaturated groups; (C) represents a polymeric unit formed by copolymerizing copolymerizable ethylenically unsaturated monomers other than those used for forming (A) and (B); x represents from 10 to 99 mol %; y represents from 0 to 10 mol %; and z represents from 0 to 90 mol %.
U.S. Pat. No. 3,992,416, issued Nov. 25, 1975 is directed to an optically clear, embossable medium for recording and storage of holographic information which comprises a transparent substrate and an embossable resin wherein the embossable resin may be polyurethane. If desired, to reduce tack, a vinyl copolymer of vinyl chloride and vinyl acetate and/or vinyl alcohol may be admixed with the polyurethane.
U.S. Pat. No. 3,158,494, issued Nov. 24, 1964, is directed to a printing substrate which contains a polyurethane layer. The patent discloses the ink-receptive surface as being solely polyurethane or pigment-containing a polyurethane.